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The Burson Audio Conductor

Everything should be made as simple as possible, but not… aw f*** it.

January, 2013

As all three of you who comprise my devoted regular readership know, the ‘D’ in the the Burson Audio HA-160D headphone amp/preamp/DAC I reviewed some months ago and have enjoyed on a quasi-daily basis since then, actually stands for “Deeply”—as in what comes after “Truly, Madly…”

I often fall into an easy “like” with a lot of stuff I review, otherwise the device under scrutiny probably wouldn’t have piqued my interest in the first place. Most times, I’ve either read about its supposed excellence, or it has else-wise caught my eye. But with the HA-160D it was love. I read about it. Everyone called it “great,” so I said “bring it!” and verily it was broughten.

No matter the musical genre and no matter the transducer, its pace, bass, dynamism and tone captured me at first listen and it also had (and has) that certain intangible something that made me wanna keep listening, wondering, “oh, what would this sound like on it? Wait, what about that track!?” Oddly, every single facet of the HA-160D was, and is, great. The preamp’s a great preamp, the DAC’s a great DAC, and the headphone amp? C’mon! Thaz waz up!!

So Mr. Burson emails me (okay, Alex at Burson) and asks do I want to hear what’s been up their collective sleeves for a long while because it improves upon the 160D in every way? So of course, I said no. No thank you. I will not stand by idly and have you muck around with perfection by improving it, damn it!

Then, after several pregnant seconds, I caved and sent them my new address. “Sure. Okay. I’ll listen to it. I guess.”

So I’m weak. We’ll inherit the earth one day—you’ll see! (Or is that the meek??) Pah. Too lazy to Google it. Same difference.

Sonically speaking…Listen, you know from the offing the Conductor isn’t gonna suck. Burson is generally incapable of making a bad sounding piece of Hi-Fi, and the follow-up to a world-beater—especially a supposedly more minimalist and high powered one (now 4 watts of output power) —is unlikely to be terrible. But would it be “better?”

In terms of the headphone amp/preamp section (also offered separately and called… wait for it… the Soloist), the nutshell of it is Burson felt they could simplify key aspects of the circuitry of the already relatively minimalist HA-160 (also contained with the 160D) such that the unit might gain in clarity/detail, lose any residual hint of solid-state grain, while at once preserving the preceding unit’s PRaT and overall sonic heft/ballsiness. The up-rated power output would also enable it to drive less efficient headphones (HiFiman HE-6, I’m tawkin’ ta YOU! Yeah- you heard me!) with greater ease and dynamics.

More specifically, the head amp/pre section sports a reduced-calorie input stage which improves upon the HA-160D’s input stage by getting entirely rid of like a third of it. Well - like a third of the components in it, anyway. One such component is an op-amp, or “operational amplifier.” An op-amp is a type of integrated circuit that amplifies a voltage differential between its two inputs. At least, that’s what I gleaned from my favorite “electronics-for-English-majors” site, http://chrisgammell.com. No, I don’t know him so it’s not a plug, but I do admire the man.

Ah, but in the world according to Burson, a single op-amp is never just a single op-amp. It is a tiny black box “…densely packed with over 50 micro components and audio signals travelling through them.” (Sounds positively choc-a-bloc with audio ill will already, no?) In the case of the HA-160D head amp/preamp section, they did away with said compact, “oy-is-it-busy-in-here” little box by thinking “out of the little box” and replacing it entirely with 32 discrete tiny components that do only specifically what Burson means them to do in the circuit. Now, since I’ve never heard a 160D with an op-amp, and can’t tell you if anyone else has either, I can’t tell you if the result is, as Burson claims, “a higher definition and more organic sound compared to any IC chip based design,” but I can tell you the HA-160D sounds Goddamned (or “bloody,” as far as you Brits are concerned) great.

Extrapolate this out-of-the-box theory to the Conductor and you now know why Burson Audio felt that in terms of the headphone amp section, “32 discrete micro components good, 21 discrete micro components must be better!” (or words to that effect). Simplify… simplify… err… you get the idea.

As far as the DAC section goes, here’s where things get interesting. In order to maximize resolution/linearity, Burson opted for the uber-techy-n-trendy ESS Sabre32 DAC chip. Pressed for whys and wherefores, Alex at Burson told me via the interwebs that “The DAC was actually a breakthrough for us…The signal output from our Sabre32/ESS9018 is fully balanced. It then goes through a passive resistor-based I/V conversion stage feeding a pure class-A FET differential gain stage which amplifies it to line level. Most other DACs before us used a common design approach to amplify the DAC's very weak signal to line level. First they implement an output stage consisting of two IC op-amps, one per channel. [Op-amps again! They screw up everything! DA]. This is followed by a buffer stage of another two IC op-amps or input tubes such as 12AU7. While the IC op-amp + tube approach inevitably colors the sound beyond acceptable levels, the IC op-amp + IC op-amp approach deviates even further from the ideal.” More about this is here.

Alex continued (via email thankfully, cause I would have really had a tough time pretending to follow the electronic-y conversation via video chat or phone). “A typical IC op-amp has over 50 micro components inside it. Using two such integrated op-amps [in the above implementation] means placing over 100 inferior components into the critical signal path. Each part blocks and distorts the signal so less is definitely more. Our tailored FET gain stage on the other hand achieves line-level amplification with only 25 discrete components directly in the signal path. Achieving our kind of magnitude of amplification with so simple a circuit is our greatest accomplishment yet. With so little components on the signal path, the sound is clean, responsive and very lively. :)” [N.B.: smiley face is his].

To be honest, I was worried. Not just because I didn’t know what “differential cascode bootstrapping” was or whatever; I was worried because most of us can list off more than a few cases of speakers, amps etc. (Are you listening Mark Levinson the brand? Or Audio Research the company? Psst. Over here. Come close Audio Research. Yeah, about those 6H30 tubes, they’re not better. They’re never better…) in which a company’s supposed technical ‘improvements’ to a solid or more than solid first effort were either at best non-existent, and at worse, should never have come into existence. I mean, there are intangibles. How do you, for example, quantify “ballsiness” on an oscilloscope and then decide you’re going to ‘increase the ballsiness’ of the new product? You’d have to know what exactly was responsible for that quality in the first place and it may be no one aspect in particular—but the sum total of several or all of them.

Your Prayers… answered?! Yes, the Conductor en masse is more detailed than the HA-160D. Yes, the Conductor is more grain-free than the HA-160D and yes, the Conductor retains the staple PRaT, dynamism and sheer musical involvement of the 160D. Whew. That was a close one.

The new Conductor didn’t answer devotees’ prayers for a remote control, but the Crocodile Dundee powers that be did grant us an improvement upon the prior 24-step stepped attenuator that graces the 160D. I criticized said attenuator regarding its (relatively) large steps (large for my for very dynamic classical music and opera recordings anyway), and here we have a solution—sort of.

The Conductor’s volume control is again a stepped attenuator, but the operation seems smoother and quieter (my imagination?) and there is provision (a button) for choosing low, medium and high gain (not my imagination, for sure). These easily toggle-able gain settings are quite helpful both in achieving a more precise volume setting when switching between headphones with differing impedances, or when optimizing the digital volume control on your front-end software (in my case Audirvana Plus 1.4—awwwwesome! Damien rules!) in order to ensure you aren’t losing bits of info by keeping the digital attenuation in a range less than 6db or so (the theoretical zero loss range).

Musically, the Conductor is really all Burson; but Burson at say, an elegant martini bar in a tux ordering a Vespers’ martini. Not that the Conductor “prettifies” or puts lipstick on a pig (Oy! God help us), but the Conductor, to me, is in essence a more refined unit than the HA-160D in much the same way the Dayens Ampino amplifier is a more refined amp than the feisty little Emotiva 50 watter.

Fortunately, God save the Queen, no PRaT was harmed in the making of the Conductor. Via either the ALO cabled Sennheiser HD600s, Shure SRH840s or the deservedly beloved Audio Technica ATH-AD900s, the HA-160D presented Kathleen Battle’s album of sacred songs entitledGrace [DG] in its usual rhythmically engaging and tonally resplendent fashion. The Conductor on the other hand (no pun intended), lost none of the 160D’s clarity or PRaT here, but now gave me the inkling that the listeners’ “window” on the event was perhaps cleaned with brand-name Windex™, rather than Marty’s Best Earthworm Organic Window Cleaner. (You tried Marty, you tried).

In particular, Battle’s voice was somewhat purer still, massed string tone had a bit more tonal weight behind the bright leading edge, and I could hear the reverb in the church venue linger on just a bit longer after vocal/orchestral tones died away.

Well-recorded piano, such as that of Yundi Li’s recital in Vienna’s legendarily sonically great Musikverein [DG], could certainly not be called “sparkly” via the HA-160D headphone amp, unless you mean that as a compliment and/or euphemism for “all the higher harmonics are intact,” though the Conductor offered improvement here too, with Li’s Bosendorfer yielding up more of that crystalline bell-tones-riding-on-a-cushion-of-air effect you hear live when encountering “great pianist in great hall with great instrument.” There was more air and rosin accompanying Nordic violinist Marianne Thorsen/Trondheim Solistene's bowings on the superbly recorded Mozart Violin Concertos [2L 38]

I wish there were a better way to put these things… but there isn’t. FYI, the Burson Conductor doesn’t make Yundi Li’s accomplished Scarlatti playing as ephemeral and buoyant as Horowitz’s; it’s an audio component, not our Father who art in heaven. Similarly, I still felt not the faintest desire to listen to Patricia Barber or Famous Blue Raincoat.

In broad terms, as far as the Conductor/HA-160D sibling rivalry is concerned, another much lazier way for me to put things is simply to agree with the several reviews and internet forum posts I’ve read, which describe the Conductor comparatively as evidencing a slight shift of sonic emphasis away from the leading edge of transients i.e. plucked and/or hammered strings (i.e. piano) and toward the “sustain” or the center of the developing tone, while at the same time seeming a touch more lit up on top and retrieving more musically relevant detail.

In other words, the Conductor both makes contact firmly and has a better follow-through on its golf swing than the HA-160D, but both are playing much better than par. Maybe for me it’s this “shift”/improved sustain, coupled with the greater articulation of micro-detail which results in a heightening of certain musical intangibles. Perhaps for example, it’s the reason meditative sections of operas, like the “quiet parts” of the famous Pavarotti/Sutherland Turandot [Decca], felt a bit more “meditative” via the Conductor, and arias like “Tu Che a Dio Spiegasti L’alli…” from the Pavarotti Lucia Di Lamermoor [Decca], a tad more pathos laden. Granted, this could also be due to the fact that Luciano Pavarotti was the greatest operatic tenor that has ever lived or ever will live. But I digress…

I owe a paragraph or so to the improved and meticulously designed USB input on the Conductor. To get it to accept the USB out from my Mac Mini, I found out I needed to download a driver from Burson. Once I figured out that’s what was needed, this took my personl assistant about, ohhh… 3 or 4 seconds. Kidding. I did it myself. A quick email to Alex and he sent me the link and presto. I primarily use the Musical Fidelity V-Link (original version) for USB to S/PDIF conversion and for good reason—I prefer the sound via a converter to direct USB input into most USB-capable DACs I’ve heard thus far.

The Conductor comes closest to being the exception to my experience in this regard. The Conductor’s USB input is first and foremost Audirvana direct integer/direct mode compatible, and it manages to preserve the space and air of the converted signal. There is superb timbre and instrumental separation as well as undiminished bass and unhardened tones. I almost thought I could dispense with my V-Link—for a bit. Then I thought I could discern, particularly with solo vocals and in operatic arias, slightly less focus to the singers’ tone. I heard this with male voices more so than with female voices. I say I ‘thought’ because the difference is on the order of diminishing returns and no doubt I could improve things with a ‘better’ USB cable (please don’t write in—I saw its face and I’m a believer).

The difference might also be more drastic were I to use a more upscale/current USB converter. I’ll get back to you on all accounts. In any case, Burson have certainly provided a viable alternative to the ‘you must use a converter’ school of thought, but I’m not fully and absolutely sonically convinced as yet.

Listen, I still love the HA-160D, but no doubt about it, the Conductor has a more refined and nuanced take on things. On the other hand, I couldn’t help but think at times that heavy metal guys (or gals) or other folk that listen to more rumpus-raisin’, booty-blastin’ music than I (like the rockin’ ‘Pavarotti and Friends’ concerts with Sting and Elton John), might feel the touch more raucous, slightly less refined sound of the HA-160D is more their bag.

Lucy, what ahm a‘splainin’ to you is…

That I feel the Conductor is truly the logical conclusion of the Burson all-in-one short story. Rather than taking an all too common misstep in uprated or SE models toward detail and ‘linearity’ ala 6H30 tubes at the expense of musical soul and engagement, with the Conductor, Burson have managed to add detail and decrease noise/grain, while at the same time adding power and features.

Comparative listening with the slightly warmer, more fulsome sounding Metrum Octave 24/96Khz DAC and the similarly ‘linear’ but less musically engaging CEntrance DAC on a standalone Soloist unit (also on hand), as well as via the Conductor itself, seem to implicate the Burson’s internal Sabre DAC circuitry as at least 51 to 63 percent responsible for this improvement. The further simplification/purification of the head/amp/preamp section and is likely responsible for the remainder. The hat trick of improved detail, functional versatility and higher power output is no easy thing. That Burson could pull this off while steadfastly refusing to compromise the intangible something-ness that made the 160D great? Well-- ‘tis rare indeed.

I hereby and forthwith proclaim, pronounce and verily decree therefore (too much Downton Abbey— the girlfriend likes it, I swear! Really, I’m just reading nearby…), that the Burson Conductor has handily and mightily outdone its (slightly) older brother; something any psychologist with an on-line PhD will tell you is impossible. Okay—unlikely at best. I’m looking forward to THIS Dr. Phil show.

Until then… I now choose to listen to the Burson Conductor in preference to the HA-160D because ‘tis forthright, herewith and straight-up-now-tell-me, the greatest headphone listening device I have yet heard. You would do well to harken unto it as well.